It is necessary in the construction of vehicles to couple all types of machine parts in an angularly movable manner. Such a mechanical connection is usually brought about by means of an elastic joint, in which a connection part, which may be spherical, among other things, and which connects the corresponding machine parts, is enclosed by a housing. The spherical part of the connection piece is mounted in the housing in an elastic intermediate layer. The housing itself is usually pressed into a bearing eye of a motor vehicle part. Such joints are maintenance-free because the mobility is achieved by the deformation of the elastic intermediate layer rather than by surfaces sliding on one another. Because of the spherical part of the connection piece, such a joint is called a “ball and socket joint.”
Such a ball and socket joint—especially for pneumatic suspensions in utility vehicles—is disclosed in EP 1 092 891 A2. The ball and socket joint comprises two metallic halves (half shells), which are placed flatly against one another with their flat sides, and from which hemispherical or semi-ellipsoidal contours are stamped out in a cap-like manner in mutually opposite directions. The combination of these two halves yields a so-called ball piece in the middle and so-called connection pieces with holes or grooves for fixing the parts to be connected elastically by means of screw connections at both ends. One of these two halves, also called “claw,” is shown in FIG. 8. The possibility of fastening mechanical parts to these halves explains the term “claw” used for such a part. The ball piece is inserted according to FIG. 7 into a cylindrical housing and is elastically connected with same via a joint body made of an elastic material (rubber), which is introduced by vulcanization. Both claws are rigidly connected with chassis and frame parts of the motor vehicle by means of the ends of the two halves, which jut out on both sides. Especially in an embodiment according to FIG. 7, the fastening is brought about by means of screws, which are introduced into the groove shown. The housing or the housings is/are usually integrated in struts and control arms, which elastically connect the corresponding chassis and frame parts.
In a ball piece designed as a rubber-metal part for mounting the chassis according to the state of the art just described, the corresponding half shells (claws with ball piece) must be manufactured for each length variant corresponding to the necessary length. This means, on the one hand, that a complete tool set is necessary for the manufacture for each variant. On the other hand, the particular manufacture of a length variant is complicated, especially because the forged part (stamped part) has so-called rigidity jumps because of its shape, which calls for a high-strength steel. Cutting of the half shells is not meaningful for cost reasons (time-consuming, large amount of waste, etc.).